1. Field of the Invention
This invention relates to a visualizing method for three dimensional standing wave sound field.
2. Prior Art Statement
A standing wave sound field can be used for example in connection with technology for contactless retention of a specimen in outer space as when the development of new materials is conducted in a space station. Further, valuable information usable for quality control of newly developed materials can be obtained by examining the behavior exhibited by voids (bubbles) in a molten specimen within a standing wave sound field. It is also important to have information about standing wave sound fields in cases where, for example, an attempt is made to improve the cleaning uniformity of an ultrasonic cleaner.
For advancing these technologies, it is necessary to understand the sound pressure distribution of three dimensional standing wave sound fields. Conventionally, however, while it has been easy to determine the sound pressure distribution of a one dimensional sound field, it has not been easy to determine the same for a three dimensional standing wave sound field because of the highly complex numerical computations and the like that have had to be made for this purpose.
The computations required in respect of a one dimensional sound field are relatively simple. Moreover, there is available the well-known method according to Kundt's experiment in which a horizontal glass tube of a diameter sufficiently smaller than the wavelength of the sound concerned is charged with powder and the plane sound field is visualized by the movement of the powder. However, this method cannot be applied to the visualization of a three dimensional standing wave sound field.